Annotations: 9IRS

Cryo-EM structure of the TCR-OKT3 complex

External Resource: Annotation

Domain Annotation: SCOP2 Classification
Domain Annotation: ECOD Classification
SAbDab Antibody Annotation
Thera-SAbDab Antibody Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Pharos: Disease Associations

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
H [auth e]	SCOP2B Superfamily	Immunoglobulin (Ig) domain-like	8054845	3000071	SCOP2B (2022-06-29)
D [auth f]	SCOP2B Superfamily	Immunoglobulin (Ig) domain-like	8054845	3000071	SCOP2B (2022-06-29)
C [auth d]	SCOP2B Superfamily	Immunoglobulin (Ig) domain-like	8054849	3000071	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
L [auth T]	Beta-Casp	e9irsT1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: Beta-Casp	ECOD (v294.2)
J [auth L]	Beta-Casp	e9irsL1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: Beta-Casp	ECOD (v294.2)
K [auth S]	Beta-Casp	e9irsS1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: Beta-Casp	ECOD (v294.2)
I [auth H]	Beta-Casp	e9irsH1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: Beta-Casp	ECOD (v294.2)
G [auth n]	Beta-Casp	e9irsn1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: Beta-Casp	ECOD (v294.2)
H [auth e]	Beta-Casp	e9irse1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: Beta-Casp	ECOD (v294.2)
B [auth b]	Beta-Casp	e9irsb1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: Beta-Casp	ECOD (v294.2)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
J [auth L], L [auth T]	Light Chain	IGKV4	Kappa	unknown \| unknown	SAbDab (2026-06-12)
I [auth H], K [auth S]	Heavy Chain	IGHV1	-	unknown \| unknown	SAbDab (2026-06-12)

Thera-SAbDab Antibody Annotation Thera-SAbDab Database Homepage

Chain	Name	Target	Provenance Source
J [auth L], L [auth T]	Muromonab	CD3E	Therapeutic SAbDab (2026-06-12)
I [auth H], K [auth S]	Muromonab	CD3E	Therapeutic SAbDab (2026-06-12)

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
J [auth L], L [auth T]	OKT3-L	-	-	-
I [auth H], K [auth S]	OKT3-H	-	-	-
G [auth n]	CD3-b	-	-	-
F [auth m]	CD3-a	-	-	-
E [auth g]	T-cell surface glycoprotein CD3 gamma chain	protein-containing complex binding protein binding binding signaling receptor binding T cell receptor binding identical protein binding signaling receptor complex adaptor activity protein-macromolecule adaptor activity molecular adaptor activity signaling adaptor activity molecular transducer activity transmembrane signaling receptor activity signaling receptor activity	cellular component organization cellular component biogenesis cellular component assembly protein-containing complex organization protein-containing complex assembly cellular process cellular component organization or biogenesis cellular response to stimulus immune response-regulating cell surface receptor signaling pathway regulation of cellular process response to stimulus signaling positive regulation of biological process cell communication cellular component organization cellular component biogenesis cellular component assembly protein-containing complex organization protein-containing complex assembly cellular process cellular component organization or biogenesis cellular response to stimulus immune response-regulating cell surface receptor signaling pathway regulation of cellular process response to stimulus signaling positive regulation of biological process cell communication positive regulation of response to stimulus immune response-activating signaling pathway immune response-regulating signaling pathway positive regulation of immune response regulation of immune system process signal transduction positive regulation of immune system process regulation of biological process cell surface receptor signaling pathway immune response-activating cell surface receptor signaling pathway immune response biological regulation T cell receptor signaling pathway regulation of response to stimulus immune system process regulation of immune response antigen receptor-mediated signaling pathway activation of immune response adaptive immune response multicellular organismal process gamma-delta T cell activation T cell activation cell activation lymphocyte activation leukocyte activation localization establishment of protein localization protein transport transport macromolecule localization intracellular protein localization establishment of localization developmental process thymic T cell selection cellular developmental process hemopoiesis cell development mononuclear cell differentiation lymphocyte differentiation positive thymic T cell selection T cell differentiation in thymus cell differentiation positive T cell selection anatomical structure development T cell differentiation T cell selection leukocyte differentiation alpha-beta T cell activation regulation of leukocyte apoptotic process regulation of lymphocyte apoptotic process leukocyte apoptotic process regulation of apoptotic process regulation of programmed cell death cell death lymphocyte apoptotic process apoptotic process programmed cell death establishment or maintenance of cell polarity	cell periphery cellular anatomical structure cell surface membrane plasma membrane external side of plasma membrane side of membrane membrane-bounded organelle intracellular anatomical structure intracellular vesicle intracellular organelle bounding membrane of organelle cytoplasmic vesicle vesicle membrane cell periphery cellular anatomical structure cell surface membrane plasma membrane external side of plasma membrane side of membrane membrane-bounded organelle intracellular anatomical structure intracellular vesicle intracellular organelle bounding membrane of organelle cytoplasmic vesicle vesicle membrane clathrin-coated vesicle endocytic vesicle membrane coated vesicle vesicle endocytic vesicle clathrin-coated vesicle membrane clathrin-coated endocytic vesicle membrane intracellular membrane-bounded organelle clathrin-coated endocytic vesicle cytoplasmic vesicle membrane coated vesicle membrane organelle cytoplasm organelle membrane protein-containing complex plasma membrane protein complex membrane protein complex alpha-beta T cell receptor complex plasma membrane signaling receptor complex signaling receptor complex T cell receptor complex
D [auth f], H [auth e]	T-cell surface glycoprotein CD3 epsilon chain	protein-macromolecule adaptor activity molecular adaptor activity SH3 domain binding protein binding binding protein domain specific binding kinase binding enzyme binding protein kinase binding protein-containing complex binding signaling receptor binding T cell receptor binding identical protein binding signaling receptor complex adaptor activity protein-macromolecule adaptor activity molecular adaptor activity SH3 domain binding protein binding binding protein domain specific binding kinase binding enzyme binding protein kinase binding protein-containing complex binding signaling receptor binding T cell receptor binding identical protein binding signaling receptor complex adaptor activity signaling adaptor activity molecular transducer activity transmembrane signaling receptor activity signaling receptor activity	cellular component organization cellular component biogenesis cellular component assembly protein-containing complex organization protein-containing complex assembly cellular process cellular component organization or biogenesis cellular response to stimulus immune response-regulating cell surface receptor signaling pathway regulation of cellular process response to stimulus signaling positive regulation of biological process cell communication cellular component organization cellular component biogenesis cellular component assembly protein-containing complex organization protein-containing complex assembly cellular process cellular component organization or biogenesis cellular response to stimulus immune response-regulating cell surface receptor signaling pathway regulation of cellular process response to stimulus signaling positive regulation of biological process cell communication positive regulation of response to stimulus immune response-activating signaling pathway immune response-regulating signaling pathway positive regulation of immune response regulation of immune system process signal transduction positive regulation of immune system process regulation of biological process cell surface receptor signaling pathway immune response-activating cell surface receptor signaling pathway immune response biological regulation T cell receptor signaling pathway regulation of response to stimulus immune system process regulation of immune response antigen receptor-mediated signaling pathway activation of immune response adaptive immune response regulation of cell-substrate adhesion positive regulation of cell adhesion regulation of cell adhesion cell-substrate adhesion positive regulation of cell-matrix adhesion cell adhesion cell-matrix adhesion positive regulation of cell-substrate adhesion regulation of cell-matrix adhesion positive regulation of cellular process regulation of biosynthetic process regulation of macromolecule metabolic process gene expression macromolecule biosynthetic process positive regulation of macromolecule biosynthetic process regulation of gene expression positive regulation of metabolic process biosynthetic process positive regulation of gene expression positive regulation of biosynthetic process regulation of macromolecule biosynthetic process metabolic process positive regulation of macromolecule metabolic process macromolecule metabolic process regulation of metabolic process multicellular organismal process gamma-delta T cell activation T cell activation cell activation lymphocyte activation leukocyte activation cell-cell adhesion mediated by integrin positive regulation of cell adhesion mediated by integrin regulation of cell adhesion mediated by integrin regulation of cell-cell adhesion mediated by integrin positive regulation of cell-cell adhesion positive regulation of cell-cell adhesion mediated by integrin cell-cell adhesion cell adhesion mediated by integrin regulation of cell-cell adhesion developmental process thymic T cell selection cellular developmental process hemopoiesis cell development mononuclear cell differentiation lymphocyte differentiation positive thymic T cell selection T cell differentiation in thymus cell differentiation positive T cell selection anatomical structure development T cell differentiation T cell selection leukocyte differentiation regulation of apoptotic process apoptotic process regulation of programmed cell death cell death programmed cell death head development animal organ development brain development nervous system development multicellular organism development cerebellum development central nervous system development metencephalon development hindbrain development system development alpha-beta T cell activation plasma membrane bounded cell projection organization cell projection organization neuron projection development generation of neurons neurogenesis neuron differentiation dendrite development neuron development cell surface receptor protein tyrosine kinase signaling pathway enzyme-linked receptor protein signaling pathway G protein-coupled receptor signaling pathway negative regulation of metabolic process negative regulation of biological process negative regulation of gene expression negative regulation of biosynthetic process negative regulation of macromolecule biosynthetic process negative regulation of cellular process negative regulation of macromolecule metabolic process regulation of signaling regulation of signal transduction signal complex assembly regulation of cell communication positive regulation of cell population proliferation regulation of leukocyte activation regulation of cell activation positive regulation of cell activation lymphocyte proliferation positive regulation of leukocyte activation regulation of leukocyte proliferation cell population proliferation positive regulation of T cell activation positive regulation of lymphocyte proliferation positive regulation of T cell proliferation regulation of cell population proliferation mononuclear cell proliferation regulation of leukocyte cell-cell adhesion positive regulation of leukocyte proliferation positive regulation of multicellular organismal process positive regulation of leukocyte cell-cell adhesion leukocyte proliferation leukocyte cell-cell adhesion positive regulation of lymphocyte activation positive regulation of mononuclear cell proliferation regulation of multicellular organismal process T cell proliferation regulation of lymphocyte proliferation regulation of T cell activation regulation of T cell proliferation regulation of mononuclear cell proliferation regulation of lymphocyte activation	cell periphery cellular anatomical structure cell surface membrane plasma membrane external side of plasma membrane side of membrane cell-cell junction anchoring junction cell junction protein-containing complex plasma membrane protein complex plasma membrane signaling receptor complex membrane protein complex cell periphery cellular anatomical structure cell surface membrane plasma membrane external side of plasma membrane side of membrane cell-cell junction anchoring junction cell junction protein-containing complex plasma membrane protein complex plasma membrane signaling receptor complex membrane protein complex signaling receptor complex T cell receptor complex immunological synapse alpha-beta T cell receptor complex neuron spine synapse neuron projection dendritic spine plasma membrane bounded cell projection somatodendritic compartment cell projection postsynapse dendrite dendritic tree cell body
C [auth d]	T-cell surface glycoprotein CD3 delta chain	identical protein binding protein binding binding molecular transducer activity transmembrane signaling receptor activity signaling receptor activity	cellular response to stimulus regulation of biological process regulation of cellular process cell surface receptor signaling pathway response to stimulus signaling biological regulation cellular process signal transduction cell communication immune response-regulating cell surface receptor signaling pathway positive regulation of biological process positive regulation of response to stimulus immune response-activating signaling pathway cellular response to stimulus regulation of biological process regulation of cellular process cell surface receptor signaling pathway response to stimulus signaling biological regulation cellular process signal transduction cell communication immune response-regulating cell surface receptor signaling pathway positive regulation of biological process positive regulation of response to stimulus immune response-activating signaling pathway immune response-regulating signaling pathway positive regulation of immune response regulation of immune system process positive regulation of immune system process immune response-activating cell surface receptor signaling pathway immune response T cell receptor signaling pathway regulation of response to stimulus immune system process regulation of immune response antigen receptor-mediated signaling pathway activation of immune response adaptive immune response developmental process thymic T cell selection multicellular organismal process cellular developmental process hemopoiesis cell activation cell development mononuclear cell differentiation lymphocyte activation lymphocyte differentiation positive thymic T cell selection leukocyte activation T cell differentiation in thymus T cell activation cell differentiation positive T cell selection anatomical structure development T cell differentiation T cell selection leukocyte differentiation alpha-beta T cell activation	cell periphery cellular anatomical structure cell surface membrane plasma membrane external side of plasma membrane side of membrane protein-containing complex plasma membrane protein complex plasma membrane signaling receptor complex membrane protein complex signaling receptor complex T cell receptor complex alpha-beta T cell receptor complex cell periphery cellular anatomical structure cell surface membrane plasma membrane external side of plasma membrane side of membrane protein-containing complex plasma membrane protein complex plasma membrane signaling receptor complex membrane protein complex signaling receptor complex T cell receptor complex alpha-beta T cell receptor complex membrane-bounded organelle intracellular anatomical structure intracellular vesicle intracellular organelle bounding membrane of organelle cytoplasmic vesicle vesicle membrane clathrin-coated vesicle endocytic vesicle membrane coated vesicle vesicle endocytic vesicle clathrin-coated vesicle membrane clathrin-coated endocytic vesicle membrane intracellular membrane-bounded organelle clathrin-coated endocytic vesicle cytoplasmic vesicle membrane coated vesicle membrane organelle cytoplasm organelle membrane
A [auth a], B [auth b]	T-cell surface glycoprotein CD3 zeta chain	identical protein binding protein binding binding protein homodimerization activity protein dimerization activity protein heterodimerization activity protein tyrosine kinase binding kinase binding enzyme binding protein kinase binding protein-macromolecule adaptor activity molecular adaptor activity molecular transducer activity transmembrane signaling receptor activity identical protein binding protein binding binding protein homodimerization activity protein dimerization activity protein heterodimerization activity protein tyrosine kinase binding kinase binding enzyme binding protein kinase binding protein-macromolecule adaptor activity molecular adaptor activity molecular transducer activity transmembrane signaling receptor activity signaling receptor activity	cellular component organization cellular component biogenesis cellular component assembly protein-containing complex organization protein complex oligomerization protein-containing complex assembly cellular process cellular component organization or biogenesis cellular response to stimulus regulation of biological process regulation of cellular process cell surface receptor signaling pathway response to stimulus signaling cellular component organization cellular component biogenesis cellular component assembly protein-containing complex organization protein complex oligomerization protein-containing complex assembly cellular process cellular component organization or biogenesis cellular response to stimulus regulation of biological process regulation of cellular process cell surface receptor signaling pathway response to stimulus signaling biological regulation signal transduction cell communication immune response-regulating cell surface receptor signaling pathway positive regulation of biological process positive regulation of response to stimulus immune response-activating signaling pathway immune response-regulating signaling pathway positive regulation of immune response regulation of immune system process positive regulation of immune system process immune response-activating cell surface receptor signaling pathway immune response T cell receptor signaling pathway regulation of response to stimulus immune system process regulation of immune response antigen receptor-mediated signaling pathway activation of immune response adaptive immune response Fc receptor signaling pathway Fc-gamma receptor signaling pathway multicellular organismal process gamma-delta T cell activation T cell activation cell activation lymphocyte activation leukocyte activation alpha-beta T cell activation	cell periphery protein-containing complex cellular anatomical structure plasma membrane protein complex membrane plasma membrane membrane protein complex Fc-gamma receptor III complex Fc receptor complex membrane-bounded organelle intracellular organelle intracellular anatomical structure Golgi apparatus organelle cell periphery protein-containing complex cellular anatomical structure plasma membrane protein complex membrane plasma membrane membrane protein complex Fc-gamma receptor III complex Fc receptor complex membrane-bounded organelle intracellular organelle intracellular anatomical structure Golgi apparatus organelle cytoplasm intracellular membrane-bounded organelle endomembrane system plasma membrane signaling receptor complex signaling receptor complex T cell receptor complex alpha-beta T cell receptor complex

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
E [auth g]	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
E [auth g]	IPR003598	Immunoglobulin subtype 2	Domain
E [auth g]	IPR032052	CD3 gamma/delta subunit, Ig-like domain	Domain
E [auth g]	IPR015484	CD3 protein, epsilon/gamma/delta subunit	Family
E [auth g]	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
E [auth g]	IPR003110	Phosphorylated immunoreceptor signalling ITAM	Repeat
D [auth f], H [auth e]	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
D [auth f], H [auth e]	IPR003598	Immunoglobulin subtype 2	Domain
D [auth f], H [auth e]	IPR015484	CD3 protein, epsilon/gamma/delta subunit	Family
D [auth f], H [auth e]	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
D [auth f], H [auth e]	IPR003110	Phosphorylated immunoreceptor signalling ITAM	Repeat
C [auth d]	IPR032052	CD3 gamma/delta subunit, Ig-like domain	Domain
C [auth d]	IPR015484	CD3 protein, epsilon/gamma/delta subunit	Family
C [auth d]	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
C [auth d]	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
C [auth d]	IPR003110	Phosphorylated immunoreceptor signalling ITAM	Repeat
A [auth a], B [auth b]	IPR024128	T-cell surface glycoprotein CD3 zeta subunit	Family
A [auth a], B [auth b]	IPR003110	Phosphorylated immunoreceptor signalling ITAM	Repeat
A [auth a], B [auth b]	IPR021663	T-cell surface glycoprotein CD3 zeta subunit/High affinity IgE receptor gamma subunit	Family

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
E [auth g]	: P09693	combined immunodeficiency due to CD3gamma deficiency lung carcinoma interstitial cystitis Pre B-cell acute lymphoblastic leukemia cutaneous lupus erythematosus lung adenocarcinoma psoriasis IgA glomerulonephritis lung cancer osteosarcoma
D [auth f], H [auth e]	: P07766	immunodeficiency 18 severe combined immunodeficiency rheumatoid arthritis gastrointestinal stromal tumor primary immunodeficiency disease Inflammation lung carcinoma psoriasis lung adenocarcinoma malignant glioma non-small cell lung carcinoma glioblastoma lung cancer Omenn syndrome cutaneous lupus erythematosus immunodeficiency 18 severe combined immunodeficiency rheumatoid arthritis gastrointestinal stromal tumor primary immunodeficiency disease Inflammation lung carcinoma psoriasis lung adenocarcinoma malignant glioma non-small cell lung carcinoma glioblastoma lung cancer Omenn syndrome cutaneous lupus erythematosus MHC class II deficiency ovarian cancer
C [auth d]	: P04234	immunodeficiency 19 severe combined immunodeficiency primary biliary cholangitis allergic contact dermatitis liver disease lung carcinoma lung adenocarcinoma Pre B-cell acute lymphoblastic leukemia lung cancer MHC class II deficiency osteosarcoma toxic encephalopathy cutaneous lupus erythematosus interstitial cystitis pancreatic intraductal papillary-mucinous neoplasm immunodeficiency 19 severe combined immunodeficiency primary biliary cholangitis allergic contact dermatitis liver disease lung carcinoma lung adenocarcinoma Pre B-cell acute lymphoblastic leukemia lung cancer MHC class II deficiency osteosarcoma toxic encephalopathy cutaneous lupus erythematosus interstitial cystitis pancreatic intraductal papillary-mucinous neoplasm psoriasis Sjogren syndrome invasive ductal breast carcinoma Omenn syndrome
A [auth a], B [auth b]	: P20963	systemic sclerosis immunodeficiency 25 oligoarticular juvenile idiopathic arthritis allergic rhinitis cutaneous lupus erythematosus hematologic disease interstitial cystitis lung carcinoma osteosarcoma Systemic Scleroderma asthma diffuse scleroderma hypothyroidism juvenile idiopathic arthritis lymphatic system disease systemic sclerosis immunodeficiency 25 oligoarticular juvenile idiopathic arthritis allergic rhinitis cutaneous lupus erythematosus hematologic disease interstitial cystitis lung carcinoma osteosarcoma Systemic Scleroderma asthma diffuse scleroderma hypothyroidism juvenile idiopathic arthritis lymphatic system disease psoriasis cancer Hashimoto thyroiditis lung cancer rheumatoid factor-negative juvenile idiopathic arthritis

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RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729. RCSB PDB uses resources of the National Energy Research Scientific Computing Center (NERSC), a Department of Energy User Facility.